Increasing the capacity of existing concrete columns

by Bassam Matty | March 24, 2026

Increasing the capacity of existing concrete columns is a common challenge for structural engineers working on adaptive re-use projects, building extensions, and structural remediation. Traditional strengthening approaches are typically passive, such as steel wrapping or carbon fibre strengthening. While widely used, these methods have inherent limitations. For any strengthening element to be effective, it must first experience strain in order to develop force.

Given that the strengthening is required to engage to the column to be augmented, any strain from the new loads will be applied to both, the existing member and the passive strengthening. In many cases, however, the existing column is already operating close to its limiting strain capacity. Any additional strain introduced to activate the strengthening system can push the original concrete and reinforcement beyond safe elastic limits.

At Ironbridge Engineering, we approach this problem differently by implementing active strengthening techniques. Our method utilises steel sections combined with controlled jacking mechanisms. Rather than waiting for the structure to strain and activate the strengthening system, the jacking process allows us to actively redistribute load from the existing column to the new augmentation members.

This approach provides two key benefits:
• It enables the strengthening members to immediately participate in load resistance.
• It ensures the original column remains within acceptable strain limits, even when additional building loads are introduced.

By actively managing load transfer, we can safely increase structural capacity while protecting the integrity of the existing structure, a critical advantage in complex upgrade and adaptive re-use projects.

For more information on increasing the capacity of existing concrete columns, contact the Ironbridge Engineering team